[PATCH 3.8 39/81] resubmit bridge: fix message_age_timer calculation

From: Kamal Mostafa
Date: Tue Oct 29 2013 - 14:14:29 EST


3.8.13.12 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Chris Healy <cphealy@xxxxxxxxx>

[ Upstream commit 9a0620133ccce9dd35c00a96405c8d80938c2cc0 ]

This changes the message_age_timer calculation to use the BPDU's max age as
opposed to the local bridge's max age. This is in accordance with section
8.6.2.3.2 Step 2 of the 802.1D-1998 sprecification.

With the current implementation, when running with very large bridge
diameters, convergance will not always occur even if a root bridge is
configured to have a longer max age.

Tested successfully on bridge diameters of ~200.

Signed-off-by: Chris Healy <cphealy@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
net/bridge/br_stp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c
index b01849a..e26f712 100644
--- a/net/bridge/br_stp.c
+++ b/net/bridge/br_stp.c
@@ -209,7 +209,7 @@ static void br_record_config_information(struct net_bridge_port *p,
p->designated_age = jiffies - bpdu->message_age;

mod_timer(&p->message_age_timer, jiffies
- + (p->br->max_age - bpdu->message_age));
+ + (bpdu->max_age - bpdu->message_age));
}

/* called under bridge lock */
--
1.8.1.2

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